The influence of soil water content on the uptake of ions by roots. II. Chloride uptake and concentration gradients in soil.
At higher soil water contents, chloride uptake by onion roots was greater, and the zones of depletion extended further. Models of ion transport were developed to account for the observed gradients and water content changes. Movement of chloride was increased by hydrodynamic dispersion caused by the water flux to the roots. Values for root absorbing power calculated from the measured uptake agreed well with values from stirred solution culture at higher soil water contents, but soil values were lower than solution values at lower water contents.